The HED Task Catalog is under development. IDs are not stable until formal release. Comments are welcome at github.com/hed-standard/hed-task/issues.

Imitation-Inhibition Task

HED task ID: hedtsk_imitation_inhibition

Family: Conflict and interference tasks

Also known as: Automatic Imitation Task, Automatic Imitation, Brass Imitation Task, Stimulus-Response Compatibility Imitation Task, Action Observation Compatibility Task

Execute an instructed finger movement while observing a congruent or incongruent action performed by another person; the congruency effect (faster responses on congruent trials) indexes automatic imitation and the cost of inhibiting observed-action representations.

Description

The Imitation-Inhibition Task (Brass, Bekkering, Wohlschlager, & Prinz, 2000) measures the involuntary tendency to copy observed actions and the executive cost of suppressing that tendency. Participants are cued to perform a simple action (e.g., lift the index finger when a number ‘1’ appears) while simultaneously viewing a task-irrelevant video of another person’s hand performing either the same action (congruent), a different action (incongruent, e.g., lifting the middle finger), or no action (neutral/static hand). The congruency effect – faster and more accurate responses on congruent than incongruent trials – indexes automatic imitation, while the interference effect (incongruent minus neutral) specifically indexes the inhibitory cost of suppressing the observed action. The paradigm is grounded in common-coding / ideomotor theory (Prinz, 1997): perceiving an action activates the same motor representations as executing it, creating response conflict when the observed and instructed actions differ. The task has become a standard probe of the human mirror system and self-other distinction. The automatic imitation effect is modulated by animacy (stronger for human than robotic agents), social context (in-group vs. out-group models), empathy, and developmental stage (weaker in young children, inverted-U trajectory). Clinical applications include autism spectrum conditions (mixed findings on reduced automatic imitation) and schizophrenia (impaired self-other distinction).

Inclusion test

An experiment is an instance of this task when its procedure matches, it manipulates at least one of the listed variables, and it records at least one of the listed measures.

Procedure

Participants perform an instructed action (e.g., finger lift) in response to a symbolic cue while simultaneously observing a task-irrelevant video or animation of another agent performing a congruent, incongruent, or neutral action.

Manipulation

Congruency (observed action matches vs. mismatches instructed action); agent type (human hand, robotic hand, non-biological stimulus); social context (in-group vs. out-group model); action type (finger lift, hand open/close, whole-arm movement); spatial compatibility control (orthogonal spatial arrangement to dissociate imitative from spatial compatibility).

Measurement

Congruency effect (RT and error rate difference: incongruent minus congruent); interference effect (incongruent minus neutral); facilitation effect (neutral minus congruent); congruency effect magnitude as individual-difference measure; EEG mu-suppression as neural index of motor simulation.

Variations

Named versions that change what the participant experiences or does. The identifier of a variation is hedvar_<task>__<variation>.

Variation

Description

Justification

Classic Finger-Lift Paradigm (Brass et al.)

hedvar_imitation_inhibition__classic_finger_lift_paradigm_brass_et_al

Lift index or middle finger in response to a number cue while observing congruent or incongruent finger lifts. The foundational paradigm. Includes spatial compatibility controls.

Canonical: respond to number cue, observe incongruent finger lift

Kinematic Paradigm (Kilner Task)

hedvar_imitation_inhibition__kinematic_paradigm_kilner_task

Participants move their arm (e.g., horizontally) while watching a model move horizontally or vertically. Automatic imitation measured by increased trajectory variance when the model’s movement is incompatible. Continuous rather than discrete measure.

Perform arm movement while observing congruent/incongruent arm; different motor effector

Hand Open/Close Variant

hedvar_imitation_inhibition__hand_open_close_variant

Open or close the hand in response to a cue while observing congruent or incongruent hand movements. Larger effector; may engage different motor representations than finger movements.

Open/close hand in response to/despite observed hand action

Animacy Manipulation

hedvar_imitation_inhibition__animacy_manipulation

Compare automatic imitation of human hand, robotic hand, and non-biological (e.g., geometric) stimuli. Tests whether the mirror system is preferentially tuned to biological agents.

Animate vs. inanimate observed movement; tests social specificity of imitation

Goal-Directed Imitation Variant

hedvar_imitation_inhibition__goal_directed_imitation_variant

Observe a model grasping an object; measure whether automatic imitation is driven by the movement kinematics or the action goal. Dissociates kinematic and goal-level motor representations.

Imitate goal vs. means; tests level of imitative representation

Vocal Stimulus-Response Compatibility

hedvar_imitation_inhibition__vocal_stimulus_response_compatibility

Hear a speech sound (e.g., ‘pa’) while producing a different sound (e.g., ‘ba’). Vocal analogue of the manual imitation-inhibition task. Tests automatic imitation in the speech domain.

Vocal response to observed action; different response modality

Controlled Imitation Task (Reverse)

hedvar_imitation_inhibition__controlled_imitation_task_reverse

Participants are cued to act but must mimic the observed action on a subset of trials. Reverses the standard task demands: measures the ability to prioritize imitation over instructed action.

Instructed to imitate or not; tests explicit voluntary control

Counter-Imitation Training

hedvar_imitation_inhibition__counter_imitation_training

Heyes et al. sensorimotor learning paradigm: train incompatible associations (see index lift, execute middle lift) to test whether automatic imitation is learned or innate. Automatic imitation is abolished or reversed after training, supporting associative sequence learning accounts.

Training to suppress imitation; tests plasticity of imitative tendencies

Cognitive processes

This task is designed to engage the following processes:

Key references

  • Brass, M., Bekkering, H., Wohlschlager, A., & Prinz, W. (2000). Compatibility between observed and executed finger movements: Comparing symbolic, spatial, and imitative cues. Brain and Cognition, 44(2), 124-143. (DOI, PubMed)

  • Heyes, C. (2011). Automatic imitation. Psychological Bulletin, 137(3), 463-483. (DOI, PubMed)

Further references

  • Cracco, E., Bardi, L., Desmet, C., Genschow, O., Rigoni, D., De Coster, L., Radkova, I., Deschrijver, E., & Brass, M. (2018). Automatic imitation: A meta-analysis. Psychological Bulletin, 144(5), 453-500. (DOI, PubMed)

  • Genschow, O., van Den Bossche, S., Cracco, E., & Brass, M. (2017). Mimicry and automatic imitation are not correlated. PLoS ONE, 12(9), e0183784. (DOI, PubMed)

  • Deschrijver, E., Wiersema, J. R., & Brass, M. (2017). Action-based touch observation in adults with high functioning autism. Social Cognitive and Affective Neuroscience, 12(2), 273-282. (DOI)

  • Kilner, J. M., Paulignan, Y., & Blakemore, S. J. (2003). An interference effect of observed biological movement on action. Current Biology, 13(6), 522-525. (DOI, PubMed)